Highly stable and active Pt electrocatalysts on TiO2-Co3O4-C composite support for polymer exchange membrane fuel cells

• TiO2-Co3O4-C composite support (CS) was synthesized and used to load 40.3 wt.% Pt for PEMFCs.
• The composite support was more corrosion resistant than XC-72.
• The Pt/CS showed slower ECSA decrease.
• After 2000 potential cycles, Pt/CS showed high stability towards agglomeration.

Motivated by addressing the support corrosion or stability issue for electro-catalysts, a carbon composite support has been prepared by wet-impregnation of nano-sized TiO2 and cobalt (II) acetate tetrahydrate together with XC-72 carbon black, followed by thermal treatment at 900 °C in a reductive atmosphere. Decomposition of cobalt acetate under thermal treatment yields TiO2-Co3O4-C composite support (CS), as is confirmed by X-ray diffraction analysis. The composite support is found to be more corrosion resistant and stable in acidic solution than that of the conventionally used carbon black, as is witnessed by the chronoamperometric response. This composite support is then used to load 40.3 wt.% Pt nanoparticles (Pt/CS) as an electro-catalyst for proton exchange membrane fuel cells. It is found that 27.9% of the electrochemical surface area (ECSA) retained in an accelerated stability test (AST) in 0.5 M H2SO4 for Pt/CS, compared with 8.4% for 39.5 wt.% Pt catalyst supported on XC-72 carbon black. The TEM image after AST for Pt/CS also confirms its improved resistance to agglomeration. The Pt/CS catalyst shows higher mass-normalized activity for methanol oxidation in 0.5 M CH3OH + 0.5 M H2SO4 and a slower activity decay relative to that of the benchmarked Pt catalyst on carbon.